The limits on human aging, which scientists have recently pegged at 115 years, may not be so certain. In fact, humans may age far longer than that.
A new study from researchers at McGill University in Canada, which assessed the lifespans of super-agers in multiple countries, came to the conclusion that the upper limit may be, essentially, indiscernible.
“We just don’t know what the age limit might be. In fact, by extending trend lines, we can show that maximum and average lifespans, could continue to increase far into the foreseeable future,” said Siegfried Hekimi, a biologist at McGill University.
To gain their findings, the researchers looked at the oldest individuals in the United States, the United Kingdom, France and Japan since 1968. While previous research, including a study released in Nature in 2016, found that evidence suggested a peak threshold of 115 years old, the McGill researchers found no such correlation.
In April, 2016, the oldest known living human, Emma Morano, who lived in Italy, passed away at the age of 117. Other centenarians, including Jeanne Calment, who lived in France to the age of 122, add to the narrative that changes in living conditions and improved medical care continue to push the limits forward.
Today, life expectancy in the United States is 79.3 years. That figure pushes past 80 years in many other countries, including Canada, Australia and most of Western Europe. Where that trend line goes in the near and distant future is up for debate.
“It’s hard to guess,” Hekimi adds. “Three hundred years ago, many people lived only short lives. If we would have told them that one day most humans might live up to 100, they would have said we were crazy.”
Overturning Previous Studies
The new study clashes with the previous Nature study that suggested a cap of 115 years on the human lifespan. In that study, researchers concluded that the biggest gains on longevity had already been made.
“Demographers as well as biologists have contended there is no reason to think that the on-going increase in maximum lifespan will end soon. But our data strongly suggest that it has already been attained and that this happened in the 1990s,” said researcher Jan Vig, a professor at the Albert Einstein College of Medicine in New York City.
“Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan,” noted Vig at the time.
While that study didn’t rule out potential age-extending factors, it took a more pessimistic view of how long humans could reasonably live.
“While it’s conceivable that therapeutic breakthroughs might extend human longevity beyond the limits we’ve calculated, such advances would need to overwhelm the many genetic variants that appear to collectively determine the human lifespan,” reported Vig.
For the new study, Hekimi suggests that a maximum age is far from certain, and that “if such a maximum exists, it has yet to be reached or identified.”
The new study, “Many possible maximum lifespan trajectories,” also appeared in the journal Nature.